He inherited the Dukedom of Exeter when his father died in 1447. A great-grandson of John of Gaunt, he might have had a plausible claim to the throne after the death of Henry VI. However, he was cruel, savagely temperamental and unpredictable, and so had little support. P.M. Kendall describes him as "dangerous", and was seen as "cruel and fierce" by contemporary Italian observers.[1]

At the Battle of Barnet, Exeter commanded the Lancastrian left flank. He was badly wounded and left for dead, but survived. Afterwards he was imprisoned, and Anne divorced him in 1472. He "volunteered" to serve on Edward IV's 1475 expedition to France. On the return voyage he fell overboard and drowned, his body being found in the sea between Dover and Calais, Fabyan saying "but how he drowned, the certainty is not known".[3] However, Giovanni Panicharolla, the Milanese envoy to the Burgundian court, was told by Duke Charles that the King of England had given specific orders for the sailors to throw his former brother-in-law overboard.[4][5]